Decomp
--- Introduction ---

This is a mathematical exercise with a very simple principle:
given a function (real of one variable x) (x)=f(g(x)) which is
composed of two functions f et g, and eventually one of the composing
functions, the exercise asks you to find the other composing function.

In practice, this exercise may call for knowledges in various fields:
linear algebra, factorization of integers, derivatives, roots right up to
knowledges in algebraic geometry.:

This exercise accepts several option parameters which change the
style and the level of difficulty. This level of difficulty varies from very
easy even for a novice, up to very hard even for a professional mathematician.